Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located in between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer.
The absorbent core can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the tradename HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body fluid.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators may include alarm devices that are designed to assist parents or attendants identify a wet diaper condition early on. The devices produce either a visual or an audible signal.
In some embodiments, for instance, inexpensive conductive threads, foils, or paper have been placed in the absorbent articles in the machine direction. The conductive materials serve as conductive leads for a signaling device and form an open circuit in the article that can be closed when a body fluid, such as urine, closes the circuit. In these embodiments, although the absorbent articles may be disposable, the signaling devices are not. Thus, the signaling devices are intended to be removed from the article and reattached to a subsequent article.
Problems, however, have been encountered in accurately identifying and interpreting signals derived from insult to the conductive layers due to the variety of absorbent articles to which signaling devices may be coupled. Further problems have been identified relating to the possible use of unknown signaling devices that may not function properly if coupled to specially designed absorbent articles.